Bug fixes

- Fixed for Slick Browser: Label display.
- Fixed for edit button for file entity.
- Fixed for full screen video.
- Fixed for widget display.

Issue by dgupaliuk: VCL fix for ESI.
Issue by dgupaliuk: Cache disabled for ESI blocks.
Issue #3072725 by dgupaliuk: Cache disabled for ESI callbacks.
Issue #3100158 by pifagor, shubham.prakash: Replace deprecated assertEqual
Issue #3072725 by dgupaliuk: Code smell fixes.
Issue #3101861 by Andreas Hansson: Page Cache Kill Switch not respected
Issue #3072725 by itsekhmistro, shumer, dgupaliuk: Avoid redirect for anonymous on first visit
Issue #3111069 by Andreas Hansson: Vary:Cookie lost

Added slashes to token replaced strings

• Issue #3114086 by RajabNatshah, mattbloomfield, jbaxton, mtdaveo, Anybody: Dropped support for [Libraries API] module. And moved the logic to Drupal core 8.9.x libraries finding way